1. Field of the Invention
This invention relates to electrical cable connectors. More particularly, the invention relates to an inner conductor cap for interconnection with an inner conductor of a coaxial cable as an inner contact of a coaxial connector.
2. Description of Related Art
Coaxial cable connectors are used, for example, in communication systems requiring a high level of precision and reliability. To create a secure mechanical and optimized electrical interconnection between the cable and the connector, prior coaxial connectors have utilized circumferential contact between a leading edge of the coaxial cable outer conductor and the connector body, such as a flared end of the outer conductor that is clamped against an annular wedge surface of the connector body, via a coupling nut.
With the outer conductor mechanically secured, the inner conductor is often allowed to longitudinally float, electrically contacted by a bias-type contact mechanism such as spring fingers engaging the inner conductor along an outer diameter surface, or, if the inner conductor is hollow, along an inner sidewall of the inner conductor bore. Representative of this technology is commonly owned U.S. Pat. No. 6,793,529 issued Sep. 21, 2004 to Buenz.
Alternatively, prior coaxial connectors have provided mechanical interconnections between the inner conductor and the inner contact via a thread-driven radial expansion and/or direct threading of the inner contact into the bore of a hollow inner conductor. The threaded elements and/or screws required for these configurations may increase manufacturing costs and/or installation complexity.
Connectors configured for permanent interconnection via solder and/or adhesive interconnection are also well known in the art. Representative of this technology is commonly owned U.S. Pat. No. 5,802,710 issued Sep. 8, 1998 to Bufanda et al. However, solder and/or adhesive interconnections may be difficult to apply with high levels of quality control, resulting in interconnections that may be less than satisfactory, for example when exposed to vibration and/or corrosion over time.
The environmental seals in prior coaxial connectors are typically located around entry paths through the connector body and therefore do not protect the electrical interconnection between the inner conductor and the inner contact from any moisture which (a) may migrate past environmental seals of the connector body, (b) is sealed within the connector during installation and/or (c) may migrate to the electrical interconnection area along the inside of the coaxial cable. An installation error and/or failure of any one of these seals may allow moisture and/or humid air to enter the connection areas of the connector where it can pool and cause corrosion resulting in significant performance degradation of the electrical connections.
A solution in the prior art is to apply dedicated interconnection seals around the inner conductor and inner contact interconnection, for example as disclosed in commonly owned U.S. Pat. No. 7,819,698 issued on Oct. 26, 2010, to Islam. However, additional seals further complicate manufacture and/or installation.
Competition in the coaxial cable connector market has focused attention on improving electrical performance and long term reliability of the cable to connector interconnection. Further, reduction of overall costs, including materials, training and installation costs, is a significant factor for commercial success.
Therefore, it is an object of the invention to provide an inner conductor cap and method of interconnection with an inner conductor of a coaxial cable that overcomes deficiencies in the prior art.